阅读说明：本技术 一种基于准零刚度的六自由度绝对位姿测量装置 (Six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity ) 是由 蒲华燕 赵晶雷 罗均 赵继云 孔庆华 丁基恒 王敏 孙翊 李宗� 柏龙 彭艳 于 2020-07-06 设计创作，主要内容包括：本发明公开一种基于准零刚度的六自由度绝对位姿测量装置,包括参考平台、待测平台、位姿解算器和六条结构相同的准零刚度支腿；分别给下端线圈与上端线圈通以方向相反的电流,此时,两线圈在其周围空间内产生电磁场,该电磁场与下磁铁和上磁铁本身的磁场产生相互作用,产生一个与弹簧刚度相反的电磁刚度,弹簧刚度与电磁负刚度相互抵消,使整个支腿的刚度接近零刚度；当待测平台发生空间内的运动时,其运动不能传递至参考平台,因此参考平台处于静止状态；此时,通过激光位移传感器可以测得六个支腿的变形量,将六组变形量分别输入到位姿解算器,通过六自由度装置的运动学正解,即可求解得到待测平台的位移和姿态。(The invention discloses a quasi-zero-stiffness-based six-degree-of-freedom absolute pose measuring device, which comprises a reference platform, a platform to be measured, a pose resolver and six quasi-zero-stiffness supporting legs with the same structure; the lower end coil and the upper end coil are respectively electrified with currents in opposite directions, at the moment, the two coils generate electromagnetic fields in the surrounding space, the electromagnetic fields interact with the magnetic fields of the lower magnet and the upper magnet to generate electromagnetic rigidity opposite to the rigidity of the spring, and the rigidity of the spring and the negative rigidity of the electromagnetic are mutually offset to enable the rigidity of the whole supporting leg to be close to zero rigidity; when the platform to be measured moves in the space, the movement of the platform cannot be transmitted to the reference platform, so that the reference platform is in a static state; at the moment, the deformation of the six support legs can be measured through the laser displacement sensor, the six groups of deformation are respectively input into the in-place attitude resolver, and the displacement and the attitude of the platform to be measured can be solved through the kinematics forward solution of the six-degree-of-freedom device.)

1. The utility model provides an absolute position appearance measuring device of six degrees of freedom based on quasi-zero rigidity which characterized in that: the system comprises a reference platform, a platform to be tested, a pose resolver and six quasi-zero stiffness support legs with the same structure, wherein two ends of each quasi-zero stiffness support leg are respectively connected with the reference platform and the platform to be tested through spherical hinges;

the quasi-zero stiffness supporting leg comprises a lower support, a spring, a shaft, a lower end coil, an upper end coil, a lower end magnet, an upper support and a laser displacement sensor, wherein the upper end magnet and the lower end magnet which are in a mutual repulsion state are respectively fixed on the shaft through two retaining rings; the lower end coil and the upper end coil which are positioned outside the two magnets are fixed on the inner wall of the lower bracket, no relative motion exists between the two coils and the lower bracket, a gap is reserved between the lower end coil and the upper end coil, and the lower end coil and the upper end coil are electrified with currents in opposite directions; one end of the shaft is connected with the end part of the inner wall of the lower bracket through a spring, and the other end of the shaft is connected with the end part of the upper bracket; the laser displacement sensors are used for measuring deformation of six supporting legs, the six laser displacement sensors input information into the pose resolver, and the displacement and the posture of the platform to be measured can be obtained through solving by the resolver.

2. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 1, wherein: the appearance structures of the upper end magnet and the lower end magnet are the same, the magnetizing directions are axial magnetizing, and the two magnets are in a repulsive state.

3. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 1, wherein: two fender rings are lower extreme fender ring and upper end fender ring respectively, upper end magnet and lower extreme magnet pass through respectively upper end fender ring and lower extreme fender ring are fixed epaxial, and two fender rings are the lock state.

4. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 1, wherein: the outer dimensions of the upper end coil and the lower end coil are the same, and the axial thickness of the coils is the same as that of the magnets.

5. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 4, wherein: the spacing width between the upper end coil and the lower end coil is equal to the axial thickness of the coils.

6. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 1, wherein: the inner diameters of the upper end coil and the lower end coil are larger than the outer diameters of the lower end magnet and the upper end magnet.

7. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 1, wherein: one end of the upper support is sleeved in the inner wall of the lower support and connected with the shaft, and the other end of the upper support is connected with the reference platform through a spherical hinge.

8. The quasi-zero stiffness-based six-degree-of-freedom absolute pose measurement device according to claim 7, wherein: the laser displacement sensor is installed on the outer wall of the non-sleeved end of the upper support, and a gap is reserved between the laser displacement sensor and the end part of the lower support.

Technical Field

The invention relates to the technical field of absolute displacement measurement, in particular to a six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity.

Background

Absolute displacement measurement is widely used in the field of active vibration control in industrial production lines, precision engineering, scientific research and other practices, and a plurality of feedback modes are widely applied, wherein absolute position feedback has distinct characteristics in the aspects of eliminating low-frequency vibration and improving robustness to external interference, and the reason is that an absolute displacement feedback-based vibration isolation system has low vibration transfer rate and low dynamic flexibility. Position feedback is typically achieved by measuring the absolute displacement of a load or device. Researchers have proposed some methods of measuring the absolute motion of an object, including integrating acceleration or velocity signals. However, the former method may introduce undesired time delay and error accumulation during the integration of the acceleration signal, which may cause the control action to fail; the latter method requires a speed sensor such as a geophone, etc., and is therefore relatively costly. Both laser displacement sensors and linear variable differential transformers can be used to measure the relative displacement between the device and the sensor, and if it is desired to measure the absolute displacement of an object, the sensor needs to be mounted at an absolutely stationary point, which is clearly impractical for absolute displacement measurements of the mobile platform and its accessories (e.g. the distance of the moving vehicle from the ground, the wave motion of a surface vessel relative to the water level, etc.).

Moreover, the above displacement measurement method can only measure a single degree of freedom, and cannot measure the displacement and the posture of an object in space. Chinese patent CN201210203199.9 discloses a measuring device and a dynamic measuring method for spatial six-degree-of-freedom motion, which can complete the motion of an object in space with six degrees of freedom, and is simple, reliable and accurate in measurement. However, the measuring device must be fixed to a stationary object before the measurement is completed, which is not practical for moving objects (such as the aforementioned traveling vehicles and ships).

Disclosure of Invention

The invention aims to provide a six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity, which is used for solving the problems in the prior art, realizing absolute stillness of a reference platform through a quasi-zero rigidity supporting leg, converting absolute motion measurement of an object to be measured into relative motion measurement, and having strong adaptability, wide measurement range and high precision.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a quasi-zero-rigidity-based six-degree-of-freedom absolute pose measuring device which comprises a reference platform, a platform to be measured, a pose resolver and six quasi-zero-rigidity support legs with the same structure, wherein two ends of each quasi-zero-rigidity support leg are respectively connected with the reference platform and the platform to be measured through spherical hinges;

the quasi-zero stiffness supporting leg comprises a lower support, a spring, a shaft, a lower end coil, an upper end coil, a lower end magnet, an upper support and a laser displacement sensor, wherein the upper end magnet and the lower end magnet which are in a mutual repulsion state are respectively fixed on the shaft through two retaining rings; the lower end coil and the upper end coil which are positioned outside the two magnets are fixed on the inner wall of the lower bracket, no relative motion exists between the two coils and the lower bracket, a gap is reserved between the lower end coil and the upper end coil, and the lower end coil and the upper end coil are electrified with currents in opposite directions; one end of the shaft is connected with the end part of the inner wall of the lower bracket through a spring, and the other end of the shaft is connected with the end part of the upper bracket; the laser displacement sensors are used for measuring deformation of six supporting legs, the six laser displacement sensors input information into the pose resolver, and the displacement and the posture of the platform to be measured can be obtained through solving by the resolver.

Preferably, the upper end magnet and the lower end magnet are the same in appearance structure, the magnetizing directions are axial magnetizing, and the two magnets are in a repulsive state.

Preferably, two keep off the ring and be lower extreme fender ring and upper end fender ring respectively, upper end magnet and lower extreme magnet pass through respectively upper end keeps off the ring and the lower extreme keeps off the ring is fixed epaxial, and two fender rings are the lock state.

Preferably, the outer dimensions of the upper end coil and the lower end coil are the same, and the axial thickness of the coil is the same as that of the magnet.

Preferably, the width of the space between the upper end coil and the lower end coil is equal to the axial thickness of the coil.

Preferably, the inner diameters of the upper end coil and the lower end coil are larger than the outer diameters of the lower end magnet and the upper end magnet.

Preferably, one end of the upper support is sleeved in the inner wall of the lower support and connected with the shaft, and the other end of the upper support is connected with the reference platform through a spherical hinge.

Preferably, the laser displacement sensor is installed on the outer wall of the non-sleeved end of the upper support, and a gap is reserved between the laser displacement sensor and the end part of the lower support.

Compared with the prior art, the invention has the following beneficial technical effects:

the six-degree-of-freedom absolute pose measuring device based on the quasi-zero rigidity can realize the absolute stillness of the reference platform through the quasi-zero rigidity supporting legs, convert the absolute motion measurement of an object to be measured into the relative motion measurement, and has the advantages of strong adaptability, wide measuring range and high precision.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is an isometric view of a six-degree-of-freedom absolute pose measurement device;

FIG. 2 is a front view of a six-degree-of-freedom absolute pose measurement apparatus;

FIG. 3 is a top view of a six-degree-of-freedom absolute pose measurement apparatus;

FIG. 4 is a cross-sectional view of the leg;

FIG. 5 is a cross-sectional view of a zero stiffness mechanism;

in FIG. 6, 6a is the motion transmissivity along the x-axis, 6b is the motion transmissivity along the y-axis, 6c is the motion transmissivity along the z-axis, 6d is the motion transmissivity about the x-axis, 6e is the motion transmissivity about the y-axis, and 6f is the motion transmissivity about the z-axis;

in fig. 7, 7a is a schematic diagram of the movement along the x-axis translation, 7b is a schematic diagram of the movement along the y-axis translation, 7c is a schematic diagram of the movement along the z-axis translation, 7d is a schematic diagram of the movement around the x-axis rotation, 7e is a schematic diagram of the movement around the y-axis rotation, and 7f is a schematic diagram of the movement around the z-axis rotation;

wherein, 1 refers to the platform; 2 quasi-zero stiffness legs; 201, spherical hinge at the lower end; 202, carrying out spherical hinge on the upper end; 203 lower support; 204 spring; 205 a shaft; 206 lower end coil; 207 upper end coil; 208 a lower end magnet; 209 upper end magnet; 210, an upper bracket; 211 lower end baffle ring; 212 upper end baffle ring; 213 laser displacement sensor; 3, a platform to be tested; and 4, a pose resolver.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity, which is used for solving the problems in the prior art, realizing absolute stillness of a reference platform through a quasi-zero rigidity supporting leg, converting absolute motion measurement of an object to be measured into relative motion measurement, and having strong adaptability, wide measurement range and high precision.

The invention relates to a six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity, which comprises a reference platform, a platform to be measured, a pose resolver and six quasi-zero rigidity support legs with the same structure, wherein two ends of each quasi-zero rigidity support leg are respectively connected with the reference platform and the platform to be measured through spherical hinges; the quasi-zero stiffness supporting leg comprises a lower support, a spring, a shaft, a lower end coil, an upper end coil, a lower end magnet, an upper support and a laser displacement sensor, wherein the upper end magnet and the lower end magnet which are in a mutual repulsion state are respectively fixed on the shaft through two retaining rings; the lower end coil and the upper end coil which are positioned outside the two magnets are fixed on the inner wall of the lower bracket, no relative motion exists between the two coils and the lower bracket, a space is reserved between the lower end coil and the upper end coil, and the lower end coil and the upper end coil are electrified with currents in opposite directions; one end of the shaft is connected with the end part of the inner wall of the lower bracket through a spring, and the other end of the shaft is connected with the end part of the upper bracket; the laser displacement sensors are used for measuring the deformation of the six support legs, the six laser displacement sensors input information into the pose resolver, and the pose resolver can solve the information to obtain the displacement and the attitude of the platform to be measured.

The lower end coil and the upper end coil are respectively electrified with currents in opposite directions, at the moment, the two coils generate electromagnetic fields in the surrounding space, the electromagnetic fields interact with the magnetic fields of the lower magnet and the upper magnet to generate electromagnetic stiffness opposite to the stiffness of the spring, and the electromagnetic stiffness is called negative stiffness because the stiffness of the spring is positive. The spring stiffness and the electromagnetic negative stiffness are mutually offset, so that the stiffness of the whole supporting leg is close to zero stiffness and is generally called as quasi-zero stiffness; when the platform to be measured moves in the space, the movement of the platform cannot be transmitted to the reference platform, so that the reference platform is in a static state; at the moment, the deformation of the six support legs can be measured through the laser displacement sensor, the six groups of deformation are respectively input into the in-place attitude resolver, and the displacement and the attitude of the platform to be measured can be solved through the kinematics forward solution of the six-degree-of-freedom device.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1 to 7, the present embodiment provides a six-degree-of-freedom absolute pose measurement device based on quasi-zero stiffness, which is composed of four parts: the system comprises a reference platform 1, six identical quasi-zero rigidity support legs 2, a platform to be measured 3 and a pose resolver 4.

In particular, the composition of the quasi-zero stiffness leg 2 is as follows:

comprises a lower end spherical hinge 201, an upper end spherical hinge 202, a lower support 203, a spring 204, a shaft 205, a lower end coil 206, an upper end coil 207, a lower end magnet 208, an upper end magnet 209, an upper support 210, a lower end baffle ring 211, an upper end baffle ring 212 and a laser displacement sensor 213. The upper end magnet 209 and the lower end magnet 208 which are in a repulsive state are respectively fixed on the shaft 205 through two retaining rings; the lower end coil 206 and the upper end coil 207 which are positioned outside the two magnets are fixed on the inner wall of the lower bracket 203, no relative motion exists between the two coils and the lower bracket 203, a space is reserved between the lower end coil 206 and the upper end coil 207, and the lower end coil 206 and the upper end coil 207 are electrified with currents in opposite directions; one end of the shaft 205 is connected with the end part of the inner wall of the lower bracket 203 through the spring 204, and the other end is connected with the end part of the upper bracket 210; the laser displacement sensors 213 are used for measuring the deformation of the six support legs, and the six laser displacement sensors 213 input information into the pose resolver 4, and the pose resolver can solve the information to obtain the displacement and the attitude of the platform 3 to be measured.

The invention relates to a six-degree-of-freedom absolute pose measuring device based on quasi-zero rigidity, and the basic principle mainly comprises two parts: the quasi-zero rigidity of the supporting leg realizes the principle and the measuring principle of the whole device.

Wherein, the realization principle of the quasi-zero rigidity is as follows:

the lower magnet 208 and the upper magnet 209 have the same appearance size, and the magnetizing directions are axial magnetizing, and the outer part between the lower magnet and the upper magnet is in a repulsive state, and the magnetizing directions are determined by two axial retaining rings: a lower retainer ring 211 and an upper retainer ring 209 are fixed to the shaft 205 in a locked state to ensure that the lower magnet 208 and the upper magnet 209 are in close contact with each other.

The lower end coil 206 and the upper end coil 207 are both fixed on the inner wall of the lower bracket 203, and there is no relative movement between the two coils and the lower bracket 203. The two coils have the same appearance size, the axial thickness of the two coils is equal to the axial thickness of the lower magnet 208 and the upper magnet 209, and the inner diameter of the two coils is slightly larger than the outer diameter of the lower magnet 208 and the upper magnet 209 so as to ensure that the two coils do not interfere with each other in axial movement. The distance between the lower end coil 206 and the upper end coil 207 is equal to the thickness of one coil.

The lower coil 206 and the upper coil 207 are energized with currents in opposite directions, respectively, and at this time, the coils generate electromagnetic fields in their surrounding space, which interact with the magnetic fields of the lower magnet 208 and the upper magnet 209 themselves to produce an electromagnetic stiffness opposite to the spring stiffness of the spring 204, which is called a negative stiffness because the stiffness of the spring 204 is positive. The spring stiffness and the electromagnetic negative stiffness cancel each other out, so that the stiffness of the entire quasi-zero stiffness leg 2 approaches zero stiffness, which is generally referred to as quasi-zero stiffness.

Further, the principle of absolute pose measurement is as follows:

because six quasi-zero rigidity landing legs 2 are in a quasi-zero rigidity state, the motion with the frequency higher than a certain value is isolated by the six quasi-zero rigidity landing legs 2, and further the motion can not be transmitted to the reference platform 1 through the landing legs. The motion transfer rate of the six-degree-of-freedom absolute pose measuring device in six degrees of freedom is shown in fig. 6. It can be seen that the motion corresponding to frequencies below the 0dB line will be attenuated and the attenuation below 20dB will reach 90%.

Therefore, when the stage 3 to be measured moves in space (including translation along the xyz three axes and rotation around the xyz three axes), the movement cannot be transmitted to the reference stage 1 (the movement here shall mean a movement within the measurement range of the apparatus), and therefore the reference stage 1 is in a stationary state. At this time, the deformation of the six quasi-zero stiffness support legs 2 can be measured by the laser displacement sensor 213, the six sets of deformation are respectively input to the in-position attitude resolver 4, and the displacement and attitude of the platform 3 to be measured can be obtained by solving through the kinematics forward solution of the six-degree-of-freedom device.

Fig. 7 is a measurement diagram of the six-degree-of-freedom absolute pose measurement device for six degrees of freedom in space (note that the y axis is out of the vertical paper).

In the present embodiment, the six quasi-zero stiffness legs 2 are arranged as follows:

the six quasi-zero stiffness supporting legs 2 are respectively a first supporting leg, a second supporting leg, a third supporting leg, a fourth supporting leg, a fifth supporting leg and a sixth supporting leg, wherein lower end spherical hinges 201 of the first supporting leg and the second supporting leg are adjacently arranged, lower end spherical hinges 201 of the third supporting leg and the fourth supporting leg are adjacently arranged, lower end spherical hinges 201 of the fifth supporting leg and the sixth supporting leg are adjacently arranged, and three groups of adjacently arranged lower end spherical hinges 201 are uniformly distributed on the top surface of the platform 3 to be measured at intervals of 120 degrees; then, the upper end spherical hinges 202 of the second supporting leg and the third supporting leg are adjacently arranged, the upper end spherical hinges 202 of the fourth supporting leg and the fifth supporting leg are adjacently arranged, the upper end spherical hinges 202 of the sixth supporting leg and the first supporting leg are adjacently arranged, and the three groups of upper end spherical hinges 202 which are adjacently arranged are uniformly arranged on the bottom surface of the reference platform 1 at intervals of 120 degrees; meanwhile, the three groups of lower end spherical hinges 201 which are adjacently arranged and the three groups of upper end spherical hinges 202 which are adjacently arranged are arranged in a staggered mode and do not correspond up and down, so that each supporting leg can have a certain inclination.

The arrangement of the six quasi-zero stiffness legs 2 is not limited to this, and the arrangement is only one of the possible ways, and can be adjusted appropriately according to the needs in the actual use process, and all the ways are within the protection scope of the present invention.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.